1. Field of the Invention
The present invention relates to a method for performing an optimal recording power calibration (OPC) and a recording medium therefor, which can enable an OPC operation to be efficiently performed in a recorder for recording data on the recording medium such as a digital versatile disc-rewritable (DVD-RW).
2. Description of the Related Art
Recently, high-density recording mediums capable of permanently recording high-quality video and audio data, for example, digital versatile discs-rewritable (DVDs-RW), have been developed, commercialized and supplied. Furthermore, recorders such as DVD-recorders for recording and reproducing data on and from the DVDs-RW have been developed, commercialized and supplied.
As shown in FIG. 1, a power calibration area (PCA) necessary for performing an optimal recording power calibration (OPC) operation and a recording management area (RMA) are assigned to a DVD-RW. The PCA and the RMA are positioned at an inner area of the disc before a lead-in zone of the disc.
When a recorder such as a DVD-recorder receives a recording command based upon a user request, an OPC operation for recording data on an optical disc normally is automatically performed. The OPC operation includes a recording operation of predetermined test data in the PCA and an adjustment operation of a recording power value so that a beta ratio value indicating an asymmetry ratio of a radio frequency (RF) signal read and detected according to the recorded test data is close to zero. In this case, one error correction code (ECC) block having a size of 16 sectors within the PCA is used from an outer circumference direction to an inner circumference direction of the disc.
Further, the RMA can contain, among other things, 28 recording management data (RMD) blocks 40a, 40b . . . , in which recording related data associated with an OPC operation are stored. Each RMD 40a, 40b, . . . defined in the DVD-RW standard contains 15 fields (Field 0˜Field 14) each of which has a size of one sector as shown in FIG. 2 depicting the fields of RMD 1 (40a).
Furthermore, the second field (Field 1) for the RMD 1 (40a) contains OPC related information. As shown in FIG. 3 depicting the Field 1 of the RMD 1, a time stamp in which 73rd to 80th bytes 48 (Byte Position 72 to 79) having a size of 8 bytes in the second field (Field 1) of the RMD 1 are recorded contains time information relating to the OPC operation. For example, as shown in FIG. 4, hour, minute and second information relating to the OPC operation is recorded in the 1st to 4th bytes of the time stamp, and year, month and day information relating to the OPC operation is recorded in the remaining 5th to 8th bytes of the time stamp. In FIG. 3, “No 1”, “No 2”, “No 3”, etc., represent different drives such that the drive manufacturer IDs in these sections are different from each other.
In the related art, however, each time a user data recording command is received, the recorder such as the existing DVD-recorder performs an OPC operation. This causes a delay in the actual user data recording, because a significant time is spent performing the OPC operation each time a recording command is received. In the related art, only one recording power value per drive is recorded in the Field 1 of the RMD 1 at any given time.
In another related art, the recorder records an OPC information such as a recording power value upon execution of a first OPC operation. No new OPC is performed. Then the recorded recording power value is used repeatedly for all data recording operations on the disc. This creates a problem because the OPC information being used may not produce an optimal data recording operation if a long time has elapsed since the first OPC operation.